second principal stress

例句：

1. 1.The engineer calculated the second principal stress in the beam.
   工程师计算了梁中的第二主应力。
2. 2.The stress distribution is affected by the second principal stress.
   应力分布受到第二主应力的影响。
3. 3. The material's strength is mainly determined by the second principal stress.
   材料强度主要由第二主应力决定。